Wheelbarrows have long been used in construction, gardening, and other home applications where loads are moved and transported from one place to another. The unique single wheel design of the traditional wheelbarrow enables a relatively heavy load to be balanced and maneuvered, with particular advantage in tight quarters. The wheelbarrow in both single wheel and double wheel designs enables a single person to transport quite heavy loads. They are very maneuverable and are cheap to manufacture. However, they do have some shortcomings. They require the operator to have strong upper body strength, plus full use of all limbs and are extremely difficult to push up slopes or over any appreciable distance on level ground.
Many attempts have been made to alleviate the aforementioned problem by motorizing the wheelbarrow. Examples include U.S. Pat. No. 5,878,827 to Fox, U.S. Pat. No. 5,489,000 to Hillbohm, U.S. Pat. No. 5,465,801 to Hoover, U.S. Pat. No. 5,305,843 to Armstrong, U.S. Pat. No. 5,211,254 to Harris, III et al, and U.S. Pat. No. 4,589,508 to Hoover et al. All of the above mentioned patents disclose gasoline powered or battery powered motors affixed to a traditional wheelbarrow to supply the drive force. While more efficient than traditional manpowered wheelbarrows, the motorized wheelbarrows still require significant manpower to maintain the balance of the overall structure while maneuvering. Thus, the motorized wheelbarrows still encounter great difficulty when used to transport heavy or unbalanced loads, or when transporting loads over particularly difficult terrain.
An additional disadvantage of the aforementioned motorized wheelbarrows is that the motor is generally located to the rear of the wheel resulting in a burden on the user to lift the motor while moving the wheelbarrow from place to place. Further, when the wheelbarrow is tipped to deliver the load, the weight of the motor remains a cantilevered burden which must be raised up to a position in which it becomes top-heavy when the load slides out of the hopper. Still further, because the motor is located below the bottom of the wheelbarrow hopper, to prevent damage to the motor the wheelbarrow must be further lifted when obstructed by stones, bricks, or other debris.
Examples of devices intended to overcome the above mentioned problems with motorized wheelbarrows are found in U.S. Pat. No. 5,284,218 to Rusher, Jr., U.S. Pat. No. 4,811,988 to Immel, and U.S. Pat. No. 4,807,716 to Hawkins. All three patents disclose four-wheel motorized carts. The motorized carts provide the same ability to maneuver heavy loads as the motorized wheelbarrows, but have added stability provided by the existence of four wheels. Further, the Rusher, Jr. patent discloses means for delivering the load without having to lift the entire motor.
While the motorized carts are advantageous over the motorized wheelbarrows, both devices share the same disadvantage of being relatively expensive to manufacture and thus needlessly expensive to the user if not needed for everyday use. The expense forecloses the infrequent user from purchasing such a product.
There exists a need, therefore, for a device that is inexpensive to manufacture and suitable for infrequent use that provides motorized transport of materials.
One way of minimizing the costs involved in a particular apparatus which may be used infrequently is to provide a multi-purpose device such as that in U.S. Pat. No. 4,090,457 to Roberts. Although not motorized, the Roberts device combines a hand operated plow which can be converted to a seed planter and fertilizer or to a wheelbarrow. The concept is also utilized in U.S. Pat. No. 5,090,142 to Peters which utilizes an attachment to convert a standard lawnmower into a snowblower when the occasion arises. Similar to a wheelbarrow, the snowblower is subject to infrequent use and it is not cost efficient to purchase the entire apparatus for once a year use.
There exists a need, therefore, for a device which provides motorized transport of materials when combined with another standard piece of equipment.